Special read-only accounts maintained by the runtime that expose cluster state to programs. Key sysvars include Clock (slot, timestamp), Rent (lamports-per-byte), EpochSchedule (epoch parameters), RecentBlockhashes, StakeHistory, and Fees. Programs access sysvars by including the sysvar account in the instruction or via the sol_get_sysvar syscall.
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Special read-only accounts maintained by the runtime that expose cluster state to programs. Key sysvars include Clock (slot, timestamp), Rent (lamports-per-byte), EpochSchedule (epoch parameters), RecentBlockhashes, StakeHistory, and Fees. Programs access sysvars by including the sysvar account in the instruction or via the sol_get_sysvar syscall.
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Accounts, instructions, PDAs, transactions, and execution flow.
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Sysvar (sysvar) Category: Programming Model Definition: Special read-only accounts maintained by the runtime that expose cluster state to programs. Key sysvars include Clock (slot, timestamp), Rent (lamports-per-byte), EpochSchedule (epoch parameters), RecentBlockhashes, StakeHistory, and Fees. Programs access sysvars by including the sysvar account in the instruction or via the sol_get_sysvar syscall. Related: Clock Sysvar, Rent Exemption, Epoch Schedule
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A sysvar (address: SysvarC1ock11111111111111111111111111111111) that provides the current slot, epoch, unix_timestamp, and leader_schedule_epoch. Programs use Clock to implement time-based logic like lockups or vesting schedules. In Anchor, accessed via `Clock::get()` or as a sysvar account in the accounts struct.
The state where an account holds enough lamports to cover two years of rent, making it effectively permanent. The minimum balance is approximately 0.00089088 SOL per byte of data. Since Solana requires all new accounts to be rent-exempt, this is the minimum funding required when creating accounts.
The configuration that defines the length of an epoch in slots and governs how epoch boundaries are calculated on a Solana cluster. On mainnet-beta, each epoch is 432,000 slots (approximately 2-3 days at 400ms per slot). The epoch schedule determines when staking rewards are distributed, when stake activations and deactivations take effect, and when the leader schedule is recalculated. It is set at genesis and queryable via the getEpochSchedule RPC method.
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Byte arrays used as inputs to derive a Program Derived Address. Seeds can be any combination of static strings, user pubkeys, mint addresses, or other identifiers (each seed max 32 bytes, up to 16 seeds). For example, seeds=[b'vault', user.key()] derives a unique vault PDA for each user.
A 64-byte Ed25519 digital signature over a transaction's message. Each signer in a transaction produces one signature. The first signature (from the fee payer) also serves as the unique transaction ID. Signature verification is parallelized in the TPU's sigverify stage using GPU acceleration.
An account that has provided a valid Ed25519 signature in the current transaction. The runtime enforces the is_signer flag on instruction account metas—if an instruction declares an account as a signer, the transaction must include its signature. Missing signer checks are a common vulnerability in Solana programs.
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A sysvar (address: SysvarC1ock11111111111111111111111111111111) that provides the current slot, epoch, unix_timestamp, and leader_schedule_epoch. Programs use Clock to implement time-based logic like lockups or vesting schedules. In Anchor, accessed via `Clock::get()` or as a sysvar account in the accounts struct.
The state where an account holds enough lamports to cover two years of rent, making it effectively permanent. The minimum balance is approximately 0.00089088 SOL per byte of data. Since Solana requires all new accounts to be rent-exempt, this is the minimum funding required when creating accounts.
The configuration that defines the length of an epoch in slots and governs how epoch boundaries are calculated on a Solana cluster. On mainnet-beta, each epoch is 432,000 slots (approximately 2-3 days at 400ms per slot). The epoch schedule determines when staking rewards are distributed, when stake activations and deactivations take effect, and when the leader schedule is recalculated. It is set at genesis and queryable via the getEpochSchedule RPC method.
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The fundamental data storage unit on Solana. Every piece of state is stored in an account identified by a 32-byte public key. Accounts hold a lamport balance, an owner program, a data byte array (up to 10MB), and an executable flag. Only the owning program can modify an account's data, but anyone can credit lamports to it.
Executable code deployed on-chain, equivalent to a smart contract on other blockchains. Programs are stateless—they store no data themselves but read/write data in separate accounts they own. Programs are compiled to SBF bytecode and loaded via the BPF Loader. Every program has a unique Program ID (its account's public key).
A single operation within a transaction that invokes a program. An instruction specifies: (1) the program ID to call, (2) an array of account metas (pubkey, is_signer, is_writable), and (3) an opaque data byte array. Programs decode the instruction data to determine which operation to perform.
An atomic unit of execution containing one or more instructions, a recent blockhash, and one or more signatures. All instructions in a transaction execute sequentially and atomically—if any instruction fails, the entire transaction reverts. Transactions have a 1,232-byte size limit (matching IPv6 MTU) and a default 200,000 CU budget.